* The chart canvas has already been created by the Dygraph object. The
* renderer simply gets a drawing context.
*
- * @param {Dyraph} dygraph The chart to which this renderer belongs.
- * @param {Canvas} element The <canvas> DOM element on which to draw.
+ * @param {Dygraph} dygraph The chart to which this renderer belongs.
+ * @param {HTMLCanvasElement} element The <canvas> DOM element on which to draw.
* @param {CanvasRenderingContext2D} elementContext The drawing context.
* @param {DygraphLayout} layout The chart's DygraphLayout object.
*
this.width = this.element.width;
// --- check whether everything is ok before we return
+ // NOTE(konigsberg): isIE is never defined in this object. Bug of some sort.
if (!this.isIE && !(DygraphCanvasRenderer.isSupported(this.element)))
throw "Canvas is not supported.";
var cb = pointsOnLine[idx];
ctx.save();
drawPointCallback(
- e.dygraph, e.setName, ctx, cb[0], cb[1], color, pointSize,cb[2]);
+ e.dygraph, e.setName, ctx, cb[0], cb[1], color, pointSize, cb[2]);
ctx.restore();
}
};
/**
* Add canvas Actually draw the lines chart, including error bars.
- * If opt_seriesName is specified, only that series will be drawn.
- * (This is used for expedited redrawing with highlightSeriesOpts)
- * Lines are typically drawn in the non-interactive dygraph canvas. If opt_ctx
- * is specified, they can be drawn elsewhere.
*
* This function can only be called if DygraphLayout's points array has been
* updated with canvas{x,y} attributes, i.e. by
* DygraphCanvasRenderer._updatePoints.
+ *
+ * @param {string=} opt_seriesName when specified, only that series will
+ * be drawn. (This is used for expedited redrawing with highlightSeriesOpts)
+ * @param {CanvasRenderingContext2D} opt_ctx when specified, the drawing
+ * context. However, lines are typically drawn on the object's
+ * elementContext.
* @private
*/
DygraphCanvasRenderer.prototype._renderLineChart = function(opt_seriesName, opt_ctx) {
var stackedGraph = g.getOption("stackedGraph");
var colors = g.getColors();
- var baseline = {}; // for stacked graphs: baseline for filling
+ // For stacked graphs, track the baseline for filling.
+ //
+ // The filled areas below graph lines are trapezoids with two
+ // vertical edges. The top edge is the line segment being drawn, and
+ // the baseline is the bottom edge. Each baseline corresponds to the
+ // top line segment from the previous stacked line. In the case of
+ // step plots, the trapezoids are rectangles.
+ var baseline = {};
var currBaseline;
var prevStepPlot; // for different line drawing modes (line/step) per series
var point = iter.next();
if (!Dygraph.isOK(point.y)) {
prevX = NaN;
+ if (point.y_stacked !== null && !isNaN(point.y_stacked)) {
+ baseline[point.canvasx] = area.h * point.y_stacked + area.y;
+ }
continue;
}
if (stackedGraph) {